UBUNTU-CVE-2023-4421

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    UBUNTU-CVE-2023-4421

    Published: 12 Dec 2023Last Modified: 22 Apr 2026
    Upstream:
    CVE-2023-4421
    Aliases:
    USN-6727-1

    Summary:

    Details: The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61.

    References: https://ubuntu.com/security/CVE-2023-4421, https://access.redhat.com/security/cve/CVE-2023-4421, https://people.redhat.com/~hkario/marvin/, https://www.mozilla.org/en-US/security/advisories/mfsa2023-53/, https://ubuntu.com/security/notices/USN-6727-1, https://www.cve.org/CVERecord?id=CVE-2023-4421

    Affected packages

    Package

    Name: nss

    Purl: pkg:deb/ubuntu/nss@2:3.28.4-0ubuntu0.14.04.5+esm13?arch=source&distro=esm-infra-legacy/trusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    2:3.15.1-1ubuntu1
    2:3.15.2-1
    2:3.15.3-1
    2:3.15.3.1-1
    2:3.15.3.1-1.1
    2:3.15.3.1-1.1ubuntu1
    2:3.15.4-1ubuntu3
    2:3.15.4-1ubuntu4
    2:3.15.4-1ubuntu5
    2:3.15.4-1ubuntu6
    2:3.15.4-1ubuntu7
    2:3.15.4-1ubuntu7.1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2023-4421 | CVE-DB